Prometheus
by Bluejay Blaze
Summary: Big Mom's Devil Fruit allows her to use souls as servants and bodyguards. But not all souls are from the living. What happens to these souls when Luffy defeats the female Yonko? And who or what are her most powerful weapons, Zeus and Prometheus?


**A/N: This is what happens when a mythology-happy Blue starts theorizing about how Big Mom's powers work. How can we tie in what was mentioned about her shaking the seas with Zeus and Prometheus to how her soul fruit was already used to create a Wonderland reminiscent of Alice's adventures? Well, if mythology serves, then Zeus would have to be a soul with the power of lightning while Prometheus is linked to flames and self-sacrifice. After all, he was the titan who spent millennia having his liver torn out and regrown every day for the sin of teaching Man how to use fire.**

Luffy wished he had Robin with him as he battled Big Mom. Or Sabo. Either of them would've been useful, though Robin knew more about ancient history and myth. On his own, the rubber captain didn't know what the names Zeus and Prometheus meant, only that they were important. He thought Sabo might've told him a story about them once, back when they were little and living in the tree house with Ace.

"God's Bolt!" A flash of lightning struck him harmlessly. Big Mom's captured souls hadn't figured out yet that lightning couldn't hurt him. Or perhaps lightning was the only thing Zeus could use. It was a distraction though; while he couldn't be hurt by it, the lightning left Luffy half-blind, blinking away spots. Which left him vulnerable to the other soul's much more worrisome power.

"Fire of Man!" Prometheus released a gout of flame, easily as impressive as anything Luffy's brothers had ever produced. It singed his clothes as he rolled out of the way.

The biggest problem with soul people though was, as far as Luffy was concerned, that he couldn't easily punch them. Zeus and Prometheus hadn't been placed in tangible bodies like most of Big Mom's lesser captured souls. Instead, Zeus was a raging thunderhead and Prometheus was a golden ball of flame. Only their shining silver eyes and booming voices convinced Luffy that they were actually people. Those eyes showed sadness. It was as if the souls didn't want to be attacking him.

Luffy's eyes went wide. Of course they didn't! Big Mom was controlling them! So if he could take her out, the souls would stop fighting and be free to go do whatever souls do. But how could he get to the Yonko past her two most powerful creations? If only he could turn them against each other somehow... Or maybe... Luffy grinned. It was worth a try.

A wave of Haoshoku Haki crashed over the battlefield, knocking many of the people watching unconscious. In the brief moment Big Mom's concentration wavered, Luffy reached to the closer soul person and grabbed them. Busoshoku Haki meant his hand didn't immediately slide through. The rubber captain tried coating the soul person with Haki the same way he knew Zoro could do with swords he was holding. And it worked. A black shield slid over flames- Luffy had grabbed Prometheus.

"Can she still control you while I'm doing this?"

"No." The fireball trembled in Luffy's grasp. "But I can't fight for you. All my energy comes from her; with you blocking her powers, I can barely hold myself together."

"Oh..." Well, that was disappointing. Luffy pouted for a moment, then forced a smile. "Hey... She took you from someone else right? You're part of someone's soul like all the others? So if I beat her, will you go back to the person you originally came from?"

"If I was like the others, yes. But Zeus and I are whole souls, captured before we could move on to the afterlife. That's why we're so much more powerful. I don't know what would happen if Big Mom released us from her power."

"So you might move on? Die?"

"Yes. But I lived a good life; I'm not afraid. My only regret is that I wouldn't be able to see my younger brother one last time. Could you give him a message for me?"

Luffy frowned. "Tell him yourself."

"But-!"

"No buts! You're a strong soul right? So you can stick around as a ghost or something and tell him! It'll mean more coming from you!"

The rubber captain sensed Prometheus' smile through his Haki. "Heh. You're probably right. Thanks kid. I like you; you remind me of my brother. Who are you anyway?"

About to answer, Luffy was suddenly struck by a giant fist. Big Mom, fed up with his possession of her soul person, sent him flying away from Prometheus. The black shield coating the fireball flickered and faded.

With Big Mom herself in the picture, the battle grew twice as hard. Luffy fought for hours without managing to gain any ground. The Yonko and her captured soul people had perfect teamwork: Zeus blinded him with lightning flashes, Prometheus kept him contained with area attacks, and Big Mom closed in to batter him with Haki. Luffy gave as good as he got, yelling loudly, growing steadily more enraged on behalf of his friends and the enslaved souls.

Big Mom threw him into a jail so hard he broke the building, landing in a jumbled pile of shattered bars. Luffy felt his strength suddenly drain. Kairoseki. Crap. He couldn't get up, couldn't escape fast enough as Zeus came towards him, and with the cursed stone there he was no longer rubber. Luffy closed his eyes and strained, trying desperately to pull himself out of the rubble. He wasn't fast enough though. White lit up the sky as the smell of ozone cut the air.

Only it didn't hit him. Luffy opened his eyes to see Prometheus standing between himself and his opponents, the fireball interspersed with tiny flecks of Busoshoku Haki. Big Mom was enraged.

"How? How dare you Prometheus? And how _can_ you? My powers hold you to this world; it's impossible for you to disobey me!"

"I don't know. My body just moved on its own."

That brief pause was enough. Luffy managed to free himself from the kairoseki rubble and launched back into the fray. "Thanks Fire Guy!"

Prometheus didn't answer. He didn't move at all. It was as if something had frozen the fire in place. But Luffy was glad of that. Without flames burning everywhere he was able to use his rubber powers properly, rather than shortening his stretches to avoid being burned. And that was exactly what he needed. Big Mom was still tough, but now he could win. And eventually he did.

Bloody, bruised, and panting, Luffy stood atop the unconscious giant of a woman. Zeus, who had been about to strike him with another bolt of lightning, dissolved from his thunderhead form. Instead Luffy saw a great bird standing before him, a beautiful golden thing with sparks crackling in its feathers and eyes like molten copper. Said bird looked totally surprised. It froze, stunned, as Luffy approached it.

"Fire Guy said you were dead," the rubber captain breathed in awe, stroking the bird's head. Anyone else would've been electrocuted; Luffy barely felt a tingle. The bird cooed, clearly not understanding its predicament but enjoying the affection. Maybe it could join his crew. It looked plenty big enough to ride, and Chopper could talk to it for him. That would be so cool!

Turning, Luffy looked to see what Prometheus had become. He expected a person, since the soul had spoken and mentioned a younger brother. Black hair and a crumpled body met his gaze. Luffy and his new bird friend raced over and rolled the unconscious man onto his back so he could breathe better. As soon as they did so, Luffy gasped.

The man's bare chest and back were marred by massive scars, as if something had pierced him right through. That was probably what had killed him. Freckles spread across skin that was far paler than it should have been- there was a sickly tinge to it, the pallor of someone kept too long from the sun. But that damage wasn't nearly enough to hide those familiar features- a sharp nose, a mouth that quirked into a smirk even in sleep. Grey eyes fluttered open.

"Lu-ffy?"

The rubber captain nodded and bit his lip, struggling to hold back tears. Ace never liked it when he cried. One or two slipped out though. Not that Luffy's big brother noticed, as he seemed to have more important things on his mind. Sitting bolt upright, Ace grabbed Luffy's shoulders and started shouting.

"Lu! What the Hell are you doing here? Did you die too? Who killed you? Shit! You were supposed to live you idiot!"

"I did!" Luffy pouted and poked Ace in the cheek, effectively shutting him up. "I'm alive, and Ace is alive now too. Big Mom captured your soul somehow and used you as some kind of freaky weapon person- don't you remember? You asked me to take a message to your younger brother."

Ace froze. Luffy watched as his older brother twitched, memories flickering across his face. Then Ace looked over at Nami, Chopper, Carrot, and Brook. "If I'm alive... The rabbit and the skeleton are some of your new crew mates?"

"Shishishi! Yep!"

"Okay..." Ace prodded experimentally at his own arm. "But I really did die, otherwise I'd still have my fruit. How- how long was I dead?"

"Two years and a bit. And don't worry about your fruit; Sabo ate it!"

"WHAT?!"

 **Several weeks later...**

It was well known that the Revolutionary Chief of Staff liked to visit his younger brother whenever his missions took him anywhere near Luffy's last known whereabouts. So when they heard that an alliance between the Straw Hat, Heart, and Whitebeard Pirates had just taken out Kaido the Beast, Koala and Hack weren't surprised at all that Sabo dragged them along to make sure Luffy was alright. What was a surprise was the freckled man sitting between Luffy and Marco who greeted them by leaping to his feet and socking their Chief of Staff in the face.

"You bastard! I thought you were dead!"

"A-Ace...?" Sabo stared dumbly, and expression that Koala thought made him look a lot like his younger brother. "H-how...?"

"Crazy lady with soul catching Devil Fruit used me as a weapon, then Luffy beat her up. He also got a pet bird out of it that's totally in love with Marco." Ace shook his head. "Don't change the subject! You died! What the Hell?!"

"I didn't die. Dragon saved me and took me back to his base. I had amnesia... All I knew was that I didn't want to go back to my parents." Sabo's eyes started to water. "Gods above and below Ace, I'm so sorry! If I'd just been there-!"

The freckled pirate suddenly had his arms full of his crying blond brother. Luffy joined in, wrapping around the both of them and bawling enough to fill a bathtub. Tears were leaking from Ace's eyes too, even as the freckled man mumbled something about hating crybabies.

Eventually, the teary ball broke apart. Sabo smirked. "Of course, you can't be Fire Fist anymore; that's my title now. You'll have to earn a new name."

Ace grinned. "Already taken care of. Just came out this morning." He held up a wanted poster for 'Undying Prince Portgas-Gol D Ace, brother of Straw Hat Luffy.' "Not the name I would've chosen, but we all know the marines are idiots. Now, who wants to help me get revenge on the bastard who killed me and almost did the same to Lu."

A dark grin spread across Sabo's face. "Oh, I think I have some ideas. How about you Lu?"

"Shishishi! Yep!"

"Count us in too." Roronoa patted his swords meaningfully. Every member of the Straw Heart Beard Alliance took on the same expression as Sabo, eyes flashing red.

Far away, Fleet Admiral Akainu sneezed as a shiver ran up his spine.


End file.
